1. Field of the Invention
This invention relates to a separation method for an adhesive tape which includes a base tape and a backing sheet laminated on the base tape. The base tape includes a base sheet and an adhesive sheet which is sandwiched between the base sheet and the backing sheet. The backing sheet is separated from the base tape by this method. The invention also relates to a device that separates the backing sheet from the base tape of the adhesive tape.
2. Description of the Related Art
Recently, due to the simplification of the application of tapes and other adhesive tapes to objects, these types of adhesive tapes are being used in various applications. In these cases, characters are imprinted on the surface of the base tape of the adhesive tape which is used as a label. The base tape on which adhesive is applied is affixed to an object after the backing paper is removed from the adhesive tape. Removing the backing paper from the adhesive tape using one's finger is extremely difficult. Various separation methods and devices have been proposed.
A separation method and device was disclosed in Japanese Laid-Open Patent Application 57-98837. In this system, as shown in FIG. 13, base tape 52 as well as adhesive 53 of adhesive tape 50 was cut with a cutter leaving backing paper 51 intact; a so-called half-cut was performed. The user would bend end member 50a, as indicated by the imaginary lines in FIG. 13, with his finger, and then using end member 50a as a handhold he would separate backing paper 51 from adhesive tape 50 (base tape 52).
In the separation method and device disclosed in Japanese Laid-Open Patent Application 5-169749, the corner of the adhesive tape was sandwiched between a punch and die and the adhesive tape was permanently deformed. In this case, due to the difference in rigidity between the base tape and the backing paper, they did not return to the same shape after being removed from the punch thus separating the backing paper from the adhesive tape. That part was used as a handhold to remove the backing paper from the adhesive sheet.
In the first separation method above, it is necessary to consistently perform the half-cut such that it cuts base tape 52 as well as adhesive 53 to a depth of several microns to several tens of microns and leaves backing paper 51 intact. Thus, it requires a high level of precision in the structure and control of the device. It was also necessary to leave about a 5-mm length at end 50a of adhesive tape 50 as a handhold for separation, thus wasting adhesive tape 50.
In the second separation method, the rigidities of the base tape and backing paper and their difference and the adhesion of the adhesive to the backing paper must be considered in setting the contact surface area and the punch depth of the punch and die. Therefore, separation was unreliable and was not satisfactory. Also, since the base tape is permanently deformed together with the backing tape, the tape tends to bend. This results in unevenness in the tape affixed to an object and makes it easier for the tape to come off the object to which it is affixed.
The invention intends to solve these problems. It provides a separation method for adhesive tape and a device with a simple structure to automate the separation. This increases the reliability and efficiency of the operation that separates the backing sheet from adhesive tape.